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I'd like to post my scenario and some background, hopefully to toggle that one DIY'ers brain and get an idea of what I'm doing wrong.

I have a 2001 Grand Cherokee 4.0. My problem started about 1.5yrs ago when the car turned off at a stop sign. Started it back up, no problems and went on my merry way. The next several weeks this got more frequent. As the temps in Chicago dropped, I found it harder and harder to start my car in the mornings. It went from 3-6 cranks to get it started, to now 40+ cranks! And when the engine does start turning over, it rough-idles for a few seconds, then sputters and dies. I wait a minute, restart, it rough idles for a minute, then sputters. After a few attempts, the car will start up and remain on, but still rough idles. I'll shut it off, and back on a few times, and the rough-idling get's less and less rough. Eventually, the car starts to act and sound normal. Now the main rub here is the following: This is not an issue in the summer time, only the winter!

Here's what my buddy and I have done so far, in order:

1. Replaced Fuel Filter and regulator (one piece) from Napa
2. Replace spark plugs with Champion Double from Napa (with .035 gap)
3. Replace Coil pack/rail from Napa (at the time of spark plugs)
4. Replaced Camshaft Position Sensor and Synchronizer from Advanced Auto (followed instructions to get engine at Top-Dead-Center by handcranking and aligned synchronizer to appropriate position before installing)

These are the following codes I keep getting> P0320, P0352, P1391

So as you can see, I'm at a loss here. This shouldn't be rocket math, it's a Jeep for Christ sake. Anyone have these symptoms and tried the efforts I have, with a different path to try next? I'm also hearing Crankshaft Sensor or O2 Sensor? What I am missing here...
 

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Well after being whipped like a dog for who knows how long with that starting and stumbling behavior, I'd disconnect the battery cables and touch them together with the key on to wipe the pcm and allow it to start relearning its parameters.

If you replaced the cps already, thats good, but you may need to circle back to it and make sure its working correctly. There are all kinds of horror stories where a cheap cps is junk right out of the box.

Im assuming (didn't look it up) "Champion Double" plugs are plain-jane copper plugs? Thats what the 4.0 engine likes, so if they aren't, replace with coppers.

By fuel filter/regulator, you are referring to which parts exactly? Is the Grand Cherokee filter located outside the gas tank? The late XJs are inside the tank.......which leads to my next idea for you: Have you investigated the fuel pump? The fuel rail should have close to 40psi of fuel pressure at all times (when keyed on or pump is on). If you aren't getting that, then you aren't getting fuel from the pump. When you key on, you should hear the pump run for a second. If you don't, its not coming on and you need to check relays and fuses for it. If those are good, move to the back and drop the gas tank. Time to replace the pump.
 

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Well after being whipped like a dog for who knows how long with that starting and stumbling behavior, I'd disconnect the battery cables and touch them together with the key on to wipe the pcm and allow it to start relearning its parameters.

If you replaced the cps already, thats good, but you may need to circle back to it and make sure its working correctly. There are all kinds of horror stories where a cheap cps is junk right out of the box.

Im assuming (didn't look it up) "Champion Double" plugs are plain-jane copper plugs? Thats what the 4.0 engine likes, so if they aren't, replace with coppers.

By fuel filter/regulator, you are referring to which parts exactly? Is the Grand Cherokee filter located outside the gas tank? The late XJs are inside the tank.......which leads to my next idea for you: Have you investigated the fuel pump? The fuel rail should have close to 40psi of fuel pressure at all times (when keyed on or pump is on). If you aren't getting that, then you aren't getting fuel from the pump. When you key on, you should hear the pump run for a second. If you don't, its not coming on and you need to check relays and fuses for it. If those are good, move to the back and drop the gas tank. Time to replace the pump.
Hi, thanks for responding.

My buddy and I got around to replacing the Crankshaft Sensor last night, what a pain. In addition, did the PCM wipe you suggested. As for the CPS, I did use one from Advance Auto and not Mopar, but its scary to think it's "junk right out of the box." The fuel-filter we replaced was under the car, bolted to the frame, so replacing it wasn't terrible.

This morning the car started up just fine, however, it was 50° outside. We'll see what happens as the temps drop even more...
 

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Hi, thanks for responding.

My buddy and I got around to replacing the Crankshaft Sensor last night, what a pain. In addition, did the PCM wipe you suggested. As for the CPS, I did use one from Advance Auto and not Mopar, but its scary to think it's "junk right out of the box." The fuel-filter we replaced was under the car, bolted to the frame, so replacing it wasn't terrible.

This morning the car started up just fine, however, it was 50° outside. We'll see what happens as the temps drop even more...
Looks like replacing the Crankshaft Sensor did the job! No more rough idles, sputtering, and Check Engine Light.
 
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